She said: “It's not a full translation. There are quite short sentences every now and again at key moments.

“The idea is that people will take their own smartphone, download the app and then they'll hear things that we think they need to know to guide them through the play.”

She hopes the app will make the theatre company’s work for accessible to non-Welsh speakers.

"We want as many people as possible to access our work," Ms Ifan said.

"People will go and see an opera in French or Italian but wouldn't think about going to see a Welsh language piece. So it's trying to entice people to make that leap."

The 2011 census showed 19 per cent of the Welsh population could speak the language, down from 21 per cent on 2001.

The app will be tested next week during a performance of Dyled Eileen, a play about the Welsh language campaigner Eileen Beasley, at the National Eisteddfod of Wales.

It will be rolled out properly in September for a play called Chwalfa being performed in Bangor, Gwynedd.

The company plan to push Sibrwd’s potential global appeal at a conference of minority European languages in Germany in October.

Ms Ifan said: “It's something we're thinking of more broadly as well, not just English-Welsh translation.

“We're looking definitely towards the international market.”

Development of the app was bankrolled by a share of £400,000 from the Digital Research and Development Fund for the Arts in Wales, which is backed by Arts Council Wales, the Arts and Humanities Research Council and innovation charity Nesta. The app is one of seven projects to share the total the Fund will be granting. Theatr Genedlaethol Cymru received £51,539 to support the development of Sibrwd.